Some of the most challenging and costly tasks undertaken by network operators when introducing new telecommunications infrastructure or adding capacity to existing infrastructure (such as adding access points (“APs” or base transceiver stations (“BTSs”, also referred to herein as “base stations”)) includes network planning, development and operational efforts. The efforts to setup and optimize such networks are significant and traditionally necessitate lengthy periods until attainment of an optimum and stable system. This is usually done based on initial, manual configuration of the BTSs at the time of deployment.
Base station neighbor information is critical for wireless network operation, for such information is utilized by base stations, network controllers and access service network (“ASN”) gateways (depending upon network architecture) for various applications, including Radio Resource Management (RRM), neighbor BTS communication associated with handoffs (handovers), and multi-step paging based on BTS neighbor topology. This neighbor information is also crucial to the successful operation of emerging, high data rate 4G wireless systems, such as those built (or to be built) in conformance with wireless specifications such as LTE (Long Term Evolution) promulgated by 3GPP (Third Generation Partnership Project) and that promulgated by the Worldwide Interoperability for Microwave Access Forum (WiMAX) for interface auto discovery. This WiMAX specification is also known as the Institute of Electrical and Electronic Engineers (IEEE) 802.16e-2005 standard, and is incorporated herein by reference.
Access points and base transceiver stations provide users (and their communications devices known as “subscriber stations”) wireless connectivity to wireless access service networks (ASN). These access points have different names depending upon network architecture and the standard to which the network is constructed, but they generally share similar characteristics, such as antenna(s) and base station transceiver(s). In cellular deployments, the antennas are mounted to physical structures, such as towers, buildings and other generally elevated structures. Once connected to the ASN, users have the ability to move about the ASN, with their call sessions (data or voice) being transferred as necessary from one base station to another. Within the network, each BTS is connected (via wireless or wireline) to a controller node. The controller node can be in the form of a “gateway” (GW) generally responsible for controlling and communicating with a number of BTSs. Such gateways can be connected to a global network, which can be the public switched telephone network (“PSTN”), Internet, or other wired or wireless communications network. It is critical for wireless network operators to ensure that call sessions maintain continuity as these call sessions are handed off from one BTS to another. As noted above, network operators typically populate lists of BTS neighbors at the time of network turn-up, but such manual configuration fails to take into account the inherently dynamic nature of networks, as planned (and unplanned) BTS service outages arise, or BTSs otherwise fully operational become unavailable for relatively short periods of time due to operation at capacities that inhibit participation in call handoffs, as can occur incident to activities such as large gatherings (e.g., major sporting and theatrical/musical events), or extraordinary events (accidents on highways, etc.).
Deployment and functioning of emerging 4G wireless technologies, such as LTE and WiMAX face many of the challenges existing in cellular/PCS networks. However, some of these challenges are more pronounced in these emerging 4G technologies as a consequence of their deployment, in many instances, at higher frequency bands (1.5 GHz to 11 GHz). One of the problems impacting such deployments concerns “shadowing”, a phenomenon involving diffraction around obstacles (such as buildings, water towers, etc.). Such diffraction becomes more problematic at higher frequencies, as the signal wavelength correspondingly diminishes. Moreover, at elevated frequencies (and depending upon prevailing RF conditions), line of sight (LOS) between the BTS and the subscriber terminal can become more of an issue. While urban areas are places where high data rates would be beneficial, these urban areas also exacerbate the LOS problem (e.g., buildings, obstacles, etc). Some locations will have no LOS, while other locations will have acceptable LOS in the vicinity of the cell site (BTS location), with poor LOS in areas further from the cell site. The 4G wireless technologies are designed for high data rates. Typically, high data rates can only be achieved with high signal-to-noise ratios (SNRs). Because LOS is not possible (or limited) in many locations, many subscriber stations are severely impacted in locations resulting in no LOS with low SNR. Often a subscriber station behind an obstacle may acquire the network (i.e., the control channel can be detected), but data throughput rates are low. A high number of users will be in disadvantaged locations that will not support high data rates between the subscriber station and BTS. Therefore, combating the shadow/LOS problem is a major issue in the deployment and operation of emerging 4G wireless technologies at higher frequencies in urban and dense urban areas.
Accordingly, there are needed infrastructure components and methods that provide self-configuration and self-optimization solutions for automatic discovery (identification or learning) of BTS neighbors (and BTS neighbor information) to avoid the individual and manual provisioning of neighbors on each BTS and controller. Such is desirable in instances of initial network deployment, capacity enhancements (such as arise from the addition of further BTSs), service outages and restarts, and other such situations that impact the network. Further, as operating conditions change in the network due to operation limitations as described above, it is important to be able to dynamically tune (i.e., identify) the list of neighbor BTSs available for handoff communications when the network conditions change (e.g., signal degradation due to shadowing (i.e., signal degradation due to physical obstructions in the path between the servicing BTS and the user, limitations in the available line of sight to the user, changes in BTS range, etc.).